Semiconductor arrangements like power semiconductor modules or the like are widely used in automotive, industrial, and consumer electronic applications for driving loads, converting power, or the like. Typically, such a semiconductor arrangement includes at least one controllable semiconductor element, each having a first load electrode, a second load electrode, a load path formed therebetween, and a control electrode for controlling the load path. In order to achieve a high rated current, the arrangement may include two or more controllable semiconductor elements electrically connected in parallel such that their load paths are electrically connected in parallel, e.g. by electrically connecting the first load electrodes to one another, and by electrically connecting the second load electrodes to one another. Optionally, also the control electrodes may be electrically connected to one another. In the ideal case, the two or more controllable semiconductor elements electrically connected in parallel are operated synchronously by feeding a common control voltage (e.g. provided by a controller) to the individual controllable semiconductor elements using electrical lines.
Because the switching state of a controllable semiconductor element, e.g. whether the load path is electrically conducting or blocking, depends on its individual control voltage, i.e. on the difference between the electric potential of the control electrode and, e.g., the first load electrode of the corresponding controllable semiconductor element, a large current flowing through a line electrically connecting the first load electrodes can, in combination with the inevitable ohmic resistance and/or inductance of that line, lead to significantly different electric potentials at the first load electrodes of the different controllable semiconductor elements. Therefore, there may be situations in which the switching states of different controllable semiconductor elements significantly differ from each other. That is, there may be instants of time at which the load paths of some of the controllable semiconductor elements are electrically conducing, whereas the control paths of the remaining controllable semiconductor elements are electrically blocking. As a result, the electric load current through the controllable semiconductor elements having their load paths connected in parallel and, therefore, the thermal and electrical load caused by the electric load current are unevenly distributed among the controllable semiconductor elements. Hereby, the lifetime of the more heavily burdened controllable semiconductor elements may be reduced. Further, different switching states may also be caused by undesired interbody-oscillations between the controllable semiconductor elements.
The described problems are, without being restricted to, of particular interest with regard to fast switching semiconductor elements like semiconductor elements based on silicon carbide (e.g. SiC-based MOSFETs or SiC-based IGBTs) because the silicon-carbide-based semiconductor chips presently available have small foot print areas and, therefore, low rated currents so that there is a frequent requirement of electrically connecting silicon-carbide-based semiconductor chips in parallel.
There is a need for a semiconductor assembly that reduces or prevents at least one of the drawbacks that can occur when the load paths of two or more controllable semiconductor elements are operated in parallel.